SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa1f081dbf682c50bd457d05e9478b2fb2a17181e094f71ae2a397750b594227' 
  AND token = 'xLNgyEfFVLr89Kh4pzK9AqpiAhvfIcyITSUvAfEv72E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}